My son loves to splash in our community pool. And I love to watch him explore the water. What I
don't love is when he opens his little mouth and sucks in a big gulp of pool water. I can't
help but look around at the hundreds of other kids and adults diving, swimming and splashing and think,
"Okay, who's peeing in the pool?"

Last summer, the Centers for Disease Control (CDC) collected water samples from 161 public and private
pools around Atlanta. E. coli, a bacterium found in the lower intestine, was discovered in most of them. In community pools like ours, 70 percent of the filters contained E. coli. More than 65 percent of samples from water parks and nearly 50 percent of samples from private pools were contaminated. There are many different strains of E. coli; symptoms of infection range from diarrhea, urinary tract infection and pneumonia. Luckily, E. coli 0157, one of the most serious and deadly strains of the disease, was not found in any of the samples.

How did E. coli get from the intestine to the pool filters? The CDC concluded that everyone brings 0.14 grams of fecal matter into the pool -- just because we don't wipe as well as we should after using the toilet. Plus, most of us don't thoroughly shower before entering the pool. And all of those cute babies and toddlers in swim diapers don't help matters, either.

"Swimmers have the power and responsibility to decrease the risk for illness by practicing good hygiene," the CDC authors write in their report. "In addition to minimizing the amount of fecal material introduced into recreational water, good swimmer hygiene, through bathroom breaks every 60 minutes and taking a pre-swim shower, minimizes the amount of urine and sweat introduced into the water."

Yes, the pools are packed with germs. And yes, we should all be wiping our rear ends a bit more thoroughly. And yes, we should take the time to shower off before diving into the pool. But what are the odds that we'll actually get sick by going swimming in a pool? Is a waterborne illness something we should really worry about? Realistically speaking, not really.

The CDC notes that, if a pool is properly chlorinated, most dangerous bacteria should be ‘neutralized' rather quickly. E. coli is killed within a minute if the pool's pH levels are adequate. Hepatitis A is killed in 16 minutes, and the Giardia parasite, which causes a diarrheal illness, is killed after 45 minutes. Some germs last longer -- Crypto, which is responsible for the diarrheal disease cryptosporidiosis, can survive for several days, even in a properly chlorinated pool.

The problem is that not all pools are properly chlorinated; a 2010 study found that 1 in 8 public pools had serious safety violations, including improper chlorine levels. Low levels of chlorine means the germs can live longer, increasing your risk for disease.

However, while the number of pool-related outbreaks of certain diseases have been on the rise, the total number of reported diarrhea-related illness is still relatively low. Last summer in Atlanta, when the CDC did their pool filter sampling, there were no pool-related diseases reported in the city, despite all those contaminated filters. And in 2010, there were 10,500 cases of Crypto (the germ that can live for days in pools). While 10,500 cases sounds like a lot, that's a relatively low number if you consider how many people swim every single day in America.

In fact, you're more likely to get swimmer's ear than E. coli by swimming in a public pool. Each year, swimmer's ear is responsible for over 2.4 million health care visits. You can prevent swimmer's ear by keeping your ears dry (using a cap or ear plugs) and drying your ears thoroughly after swimming. Proper chlorine levels are important for preventing swimmer's ear, too, so be sure to check with your pool's maintenance staff to ensure they are monitoring the chlorine levels. The CDC recommends checking the levels twice a day.